CprE 310 Russell
Spring 2002
Tues - Jan 15, 2002
http://www.ee.iastate.edu/~russell/cpre310.s02/cpre310lectr/
ASSIGNMENTS Hidden Message Project
DESCRIPTION We often read about hidden messages or see it on TV where someone claims to have studied a text and found a "hidden message" in the text.  This project will let you explore this concept and decide for yourself about the validity of hidden massage claims.

The first step of the project is to create a large text file of english letters.  The size of these files should be from 50K to 500K characters.  This can be done with a random number generator which maps one of 26 numbers into a letter (A=1, B=2 etc.).  Don't put any spaces in the text.

Start searching the large file for your name by using an arithmetic progression for the character position.  For example, if you have a 4-character name, you would search the character positions as

L1 = n + 1*d
L2 = n + 2*d
L3 = n + 3*d
L4 = n + 4*d

where "L" is the letter in your name, "n" is the location of the starting letter in the file of random letters, and "d" is the number of spaces you skip to the next letter to test.  You vary "n" and "d" until you find your name.

Use any reasonable programming method you have available.

THIS PROJECT WILL BE WORTH 100 POINTS

DUE DATE IS FEBRUARY 19, 2002

What to hand in:

  • Printout of computer source code used for the project
  • 1-2 page summary of results.  Report how many times your name was found and with what size files for several different random file sizes.  Report the values of n and d that resulted in your name being found.


 

. Copyright (c) 2001 Steve F. Russell